Slip joint for drill stems



Feb. 9, 1932. R. A. LINCOLN 1,844,257

SLIP JOINT FOR DRILL STEMS Filed March 9, 1929 BY HQ A TTORVE Y PatentedFeb. 9, 1932 UNITED STATES nomm'r a. LINCOLN, or wrcnrra FALLS, 'rnxnsBLIP JOINT FOB DRILL STEHS Application fled larch 8, 1929. Serial No.845,688.

My invention relates to a device to be placed in drill stem employed mwell drillmg which will enable the driller to place a continuous andequal weight upon the drill 6 durin the drilling operation.

- In deep well drilling for oil, gas, sulphur, and the like, the drillis found to run smoother and more effectively if an equal and steadyweight is allowed to rest upon the drill. This weight should not be tooheavy but it should be sifiicient to exert a thrust upon the bit sufi:ient to force it into the formation WhlCh is l" eing drilled. Thediificulty is to keep the weight uniform and to prevent the weight 1from becoming excessive. The total weight of the drill stem above adrill bit is sometimes far greater than the bit is enabled to su port.

t is an object of my invention to prov1 de a slip joint in the drillstem WhlCh w1ll enable the driller to suspend the upper portion of thedrill stem from the derrick platform and to allow only the lower portionof the drill stem to rest upon the b1t so that the weight of the pipesupported by the drill stem can be accurately determined and adjusted.

It is a further object 1n devices of this kind to provide a slip jointwhich may be 0 adjusted to prevent relative sliding movement of the twoparts of the drill stem whlle the drill is being inserted into the wellbut which is capable of release when the'drill stem is rotated with thedrill upon the bottom of the hole.

It is a further object to provlde effective means to revent the u perand lower sections of t e drill stem rom becoming connected again duringthe drilling operations.

The invention lies largely in the particular construction andarrangement of the parts making up the improved tool and reference ismade to the drawings herewith wherein a preferred embodiment thereof isdisclosed.

In the drawings, Fig. 1 illustrates a central longitudinal section throuh the joint forming the subject matter 0 my invention.

Fig. 2 is a transverse section, somewhat is threaded at, 2 forengagement with a collar or tool joint 3, which in turn is connectedwith the joint at the lower end of the upper section of the drill stem.The barrel 1 is of any length but ordinarily a section of about 20 or 22feet in length is preferred as this allows the telescoping of the jointfor a full section of drill stem. The lower end of the barrel isthreaded for connection at 4 with a special coupling 5.

The coupling 5 is secured to the lower end of the barrel and its innerdiameter is decreased to form a shoulder 6 above which it, isthreaded at7 for engagement with the head 8 on the drive stem 9. The lower end ofthe nipple 5 is threaded at 10 to receive the bushing 11.

The bushing 11 is provided with a threaded portion 12 to engage withinthe threaded seat 10 of the nipple 5 and above the threaded portion thediameter is decreased and formed into an upwardly extending sleeve 13 totelescope within the nipple 5. The lower end of the bushing 11 has ahead 14 thereon for engagement with a wrench or other tool by means ofwhich it may be unscrewed from the nip le 5v The drive stem 9 is ormedto fit within the bushing 11 and has a plurality of radially extendingkeys or splines 15 to fit within corresponding keyways 16 1;" thebushing 11. This will be noted front-Fig. 2; I have shown four splinesupon the drivestem .9 engaging within the bushing, but any desirednumber may be used. This engagement between the stem and the bushingallows a telescopic movement between the parts, but prevents relativerotation. The lower end of the drive stem is formed with a tool jointpin 17 thereon to engage within the lower section of drill stem, but itis to be understood that any type of coupling between the stem and thetool joint below may be employed.

The upper end of the drive stem 9 is threaded to engage within the head8, which is adapted tobe screwed thereon, said head being threadedexternally at its lower .end

for engagment at 7 with the nipple 5. Above,

the head 8, I provide packing means to form a fluid tight contact withthe interior of the barrel 1. This packing device is shown as being madeup of an upper cup 18, which is directed upwardly toprevent the passa eof fluid downwardly past the packing. 1S packing ring is separated froma second lower packing ring 19 by a spacer 20. The lower acking ring isdirected downwardly as will be noted from the drawings. ,Above and belowthe two packing rings thus mounted are washers 21 and the entire packingassembly thus constructed is held in place b a lock .nut 22 threadedupon the upper en of the drive stem. .It will be noted that the head 8,together with the packin members, comprise a sort of piston slidab ewithin the barrel 1 when the ead 8 is disengaged from the ni ple 5.

t is to be understood that. the drive stem 9 is of the same or slightlygreater length than is the barrel 1 so that the head 8 may slideupwardly in the barrel for approxmately the full length of said barrel.The interior of the drive stem 9 is formed with a water passage 23 sothat fluid may pass downwardly through the joint during the operation ofthe drill.

When the device is to be introduced into the well, the lower section ofthe drill stem is connected to the joint 17, the drill being at thelower end of the drill stem. The bushing 11 and the head 8 are threadedinto the nipple 5, approximately as shown in Fig. 1, and the uppersection of the drill stem is connect ed with the barrel 1, as previouslynoted. As the device is introduce into the well 1t will be possible toforce the drill downwardly to the bottom of the well without telescopingthe joint between the drive stem 9 and the barrel 1. If obstacles areencountered during the introduction of the drill into the well the fluidcirculation through the drill will be suilicient, with a slight rotationthereof, to force the drill past such obstacles until the bottom of thewell is reached.

When the drill is upon the bottom of the hole the drill stem will thenbe rotated. This rotation communicated to the upper section of the drillstem will rotate the barrel 1 and the nipple 5 to screw said nippledownwardly upon the bushing 11. This will also screw the said nipple offof the head 8 on the drive stem.

When the head 8 has been disconnected in this manner it is free to slideupwardly in the barrel 1, and due to the fact that the coupling 5 isscrewed down over the bushing 11 the upper gortion 13 of the bushingwill project upwar ly past the threaded seat 7 and prevent the head 8from again being screwed into the seat 7. With the parts thus disconnected the upper section of the drill stem may first allow the uppersection of the drill stem to drop downwardly over the drive stem 9 untilthe parts are entirely telescoped together, then by supporting the uppersection rom the derrick and rotatin" t e drill, the progress of thedrill downwardly through the formation will cause -it to adually movedownwardly relative to the arrel 1 until it has drilled a sufiicientdepth to allow the insertion of another section of drill stem at theupper end of the string. When this is done, the parts will be againtelescoped together and the o eration repeated.

It will e seen that by my device a uniform weight will be supported uponthe drill at all times so that best results may be obtained. It will bedetermined by the driller through experiment exactly what weight ofdrill stem is most effective in the operation of the drill and the jointmay be located in the string at tlaie proper point to obtain the. weightdesire The advantages of my construction lie in the fact that the partscan not telescope together durin the introduction of the drill stem intothe ole, due to the manner in which they are connected during thetimethe drill is being inserted to the bottom. Thus if an obstruction isencountered in the well which might tend to cause the upper and lowersections at each side of the 'oint to be telescoped together they willbe he d from so doing by my connection. This will prevent the accidentswhich are liable to hap en from telescopic joints in the drill stem, ueto the dropping of the lower section of stem away from the u per oneafter the obstruction is passed. Furt ermore, it will be impossible tomake the connection between the head 8 and nipple 5 during the drillingoperation, due to the osition of the bushing 11 when the parts are'sconnected. The further advanta es of the device will be obvious tothose ski ed in the art.

What I claim as new is;

1. A slip joint for drill pipe including two sections, one slidablerelative to the other, means on one section enga eable by means on theother to hold the sa1d sections from relative longitudinal movementreleasable on relative rotation, and means to thereafter prevent similarengagement of said sections.

2. In a drill pipe, a slip joint including a barrel a drive stem, apiston head thereon slidable in said barrel, a nip le on said barrel, abushing engageable in sai nipple, and nonrotatably engaging said drivestem.

3. In a drill pipe, a slip joint including a barrel, a drive stem, apiston head thereon slidable in said barrel, a n1p le on said barrel, abushing engageable in sai nipple and nonrotatably engaging said drivestem, said head being releasably connected with said nipple.

4. In a drill pipe, a slip joint including a barrel, a drive stem, apiston head thereon slidable in said barrel, a nipple on said barrel, abushing engageable in said nipple and nonrotatably engaging said drivestem, said head being screwed into connection with said nipple andreleasable on rotation of said pipe.

5. In a drill pipe, a slip joint including a barrel, a drive stem, aplston head thereon slidable in said barrel, a nipple on said barrel, abushing engageable in said nipple and nonrotatably engaging said drivestem, said head having a threaded connection with said nipple releasableon rotation of said drill pipe relative to said stem, and means tothereafter prevent engagement of said threaded connection.

In testimony whereof I hereunto aflix my signature this 4th dagof March,A. D. 1929.

ROB RT A.- LINCOLN.

